Tilt mechanism for chairs or the like

ABSTRACT

A tilt mechanism for a chair or the like including an upright spindle having a headpiece and a supporting member surrounding the headpiece, pivotally mounted thereon for rearward rocking movement. The bottom of the supporting member has a curved cam surface and there is provided a nylon operating member axially slideable on the spindle and having a generally flat upper cam surface in contact with the curved cam surface of the supporting member. A bushing is threadably mounted on the spindle below the operating member for adjustable movement therealong and a compression spring surrounds the spindle interposed between the bushing and the operating member urging the supporting member into its normal position.

[lite Elem 1 1 Gilbert States TILT MECHANISM FOR CHAIRS OR THE LIKE [75] inventor: Roy 0. Gilbert, Gardner,Mass.

Company,

[58'] Field of Search ..248'/37l, 372, 376, 378, 381, 248/382, 384, 398; 297/304, 305

[56] References Cited UNITED STATES PATENTS 3,220,687 11/1965 Baermann ..248/382 3,417,956 12/1968 Helms ..248/378 FOREIGN PATENTS OR APPLICATIONS 180,474 6/1922 Great Britain ..24s 3s 2 lMarch 13, 1973 328,370 3/1958 Switzerland ..248/378 Primary ExaminerMarion Parsons, Jr.

7 Attorney-R. W. Furlong [57] ABSTRACT A tilt mechanism for a chair or the like including an upright spindle having a headpiece and a supporting member surrounding the headpiece, pivotally mounted thereon for rearward rocking movement. The bottom of the supporting member has a curved cam surface and there is provided a nylon operating member axially slideable on the spindle and having a generally flat upper cam surface in contact with the curved cam surface of the supporting member. A bushing is threadably mounted on the spindle below the operating member for adjustable movement therealong and a compression spring surrounds the spindle interposed between the bushing and the operating member urging the supporting member into its normal position.

7 Claims, 3 Drawing Figures l TILT MECHANISM FOR CHAIRS OR THE LIKE This invention relates to tilt mechanisms for chairs and the like.

Although tilt mechanisms have long been known and used in so-called office posture chairs, those heretofore known have been deficient in some respects, especially as to bulkiness of construction.

Supporting member 18 surrounding headpiece 14 is pivotally mounted thereon for rearward tilting movement about a transverse horizontal axis H longitudinally forwardly spaced from the vertical axis V of said spindle by means of a bolt 12 extending through side walls 19 of supporting member 18 and side walls 11 of Accordingly, it is a major object of the present invention to provide a novel tilt mechanism not subject to the above deficiency.

This has been accomplished by providing a tilt mechanism comprising an upright spindle with a headpiece mounted on it, a supporting member surrounding the headpiece and pivotally mounted on it for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of the spindle, an operating member having a bore concentric with the spindle and slideable therealong and spring means urging the operating element into contact with the supporting member, the latter and the operating member having cooperating cam surfaces including a curved cam surface on one of the members, preferably the supporting member, and a flat cam surface on the other of the members, providing in their normal position a transverse horizontal line of contact generally coincident with the axis of the spindle. Stop means may be interposed between the headpiece and the supporting member limiting the extent of rocking movement thereof. Preferably, the spring means consists of a compression spring surrounding the spindle interposed between the operating member and an underlying adjustable bushing, the latter elements having concentric sleeve elements overlapping one another to conceal the spring.

For the purpose of more fully explaining the above and further objects and features of the invention, reference is now made to the following detailed description of a preferred embodiment of the invention, taken together with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional rear elevational view of the preferred embodiment of the tilt mechanism of the invention;

FIG. 2 is a cross-sectional side view of the embodiment of FIG. 1 with the elements of the tilt mechanism in their normal position; and

FIG. 3 is a cross-sectional side view of the embodiment of FIG. 1 with the elements of the tilt mechanism in their tilted position.

Referring to the drawings, the novel tilt mechanism of the present invention includes an upright spindle 16 having a vertical axis. Spindle 16 is mounted for adjustable vertical positioning in a base as known in the art. A headpiece, generally designated 14, is mounted on saidspindle. l-leadpiece 14 is in the form of a tubular box section having upper and lower walls 13.

and 15, respectively, connected by said walls 11, the

upper end of spindle 16 being received in suitable bores of said upper and lower walls generally centrally thereof. Surrounding headpiece 14 is a supporting member, generally designated 18, including an upper wall 17, to which may be attached a chair or the like element in a known manner, and side walls 19 extending downwardly therefrom. A downwardly curved cam plate 28, having a central opening for spindle 16, extends between the bottom edges of side walls 19.

headpiece 14. Lower stops 30 and upper stops 31, respectively mounted on the upper side of cam plate 28 on the rearward end thereof and on the bottom of upper wall 17 of supporting member 18 adjacent the rearward edge of upper wall 13 of headpiece 14, are interposed between headpiece 14 and supporting member 18 to limit the extent of tilting movement between a normal position (FIG. 2) in which lower stops 30 are in contact with the lower wall 15 of headpiece 14 and a rearwardly tilted position (FIG. 3) in which upper stops 31 are in contact with the upper wall 13 of headpiece 14.

A cup-like operating member 20 having a bore concentric with spindle 16, is mounted thereon for sliding movement therealong. Operating member 20 has a generally flat upper cam surface 21 in contact with the curved cam surface 28 of supporting member 18, providing in the normal position of said members (FIG. 2) a transverse horizontal line of contact L generally coincident with the axis of spindle l6. Said surfaces are spaced from one another at least rearwardly of said line of contact in said normal position (FIG. 2). Operating member 20 is preferably of nylon or like low friction plastic material and has a downwardly extending sleeve 25.

For urging operating member 20 upwardly into contact with supporting member 18 there is provided a cup-like bushing 23 threadably mounted on said spindle below operating member 20 for adjustable movement therealong, said bushing having a concentric sleeve 24 telescopically overlapping sleeve 25 of operating member 20. A compression spring 22' within said sleeves surrounds spindle l6 and is interposed between the inner end surfaces of bushing 23 and operating member 20 urging said supporting member into its normal position (FIG. 2), spring 22 being concealed by the overlapping sleeves of said bushing and operating member.

In operation, spring 22 normally urges operating member 20 upwardly, pivoting supporting member 18 about axis H of bolt 12 until lower stops 30' contact lower wall 15 of headpiece 14, thus maintaining supporting member 18 in its normal position (FIG. 2). When rearward tilting force is applied to supporting member 17, it tilts rearwardly, forcing operating member 20 downwardly against the force of spring 22 until upper stops 31 contact upper wall 13 of headpiece 14 (FIG. 3). The force of spring 22 may be adjusted by turning bushing 23 along spindle 16.

What is claimed is:

l. A tilt mechanism for a chair or the like comprismg:

an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle an operating member having a bore concentric with said spindle and movable therealong and means urging said operating element into contact with said supporting member said supporting member and said operating member having cooperating cam surfaces including a curved cam surface on one of said members and a flat cam surface on the other of said members providing in the nonnal position of said members a transverse horizontal line of contact generally coincident with the axis of said spindle.

2. A tilt mechanism as claimed in claim 1 further including stop means interposed between said headpiece and said supporting member limiting the extent of tilting movement thereof.

3. A tilt mechanism for a chair or the like comprising:

an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle, the bottom of said supporting member having a downwardly curved cam surface an operating member having a bore concentric with said spindle and mounted thereon for sliding movement therealong, said operating member having a generally flat upper cam surface in contact with the curved cam surface of said supporting member, providing in the normal position of said members a transverse horizontal line of contact generally coincident with the axis of said spindle with said surfaces spaced from one another rearwardly of said line of contact with said operating member in a raised position and means urging said surfaces into contact with one another and into said normal position.

4. A tilt mechanism as claimed in claim 3 wherein said means urging said surfaces into contact with one another and into said normal position comprises a bushing mounted on said spindle below said operating member for adjustable movement therealong and a compression spring surrounding said spindle interposed between said bushing and said operating member urging said supporting member into its normal position.

5. A tilt mechanism for a chair or the like comprising:

an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle, the bottom of said supporting member having a downwardly curved cam surface stop means interposed between said headpiece and said supporting member limiting the extent of tilting movement between a normal position and a rearwardly tilted position an operating member having a bore concentric with said spindle and mounted thereon for sliding movement therealon said operating member having a generally fla upper cam surface in contact with the curved cam surface of said supporting member, providing in the normal position of said members a transverse horizontal line of contact generally coincident with the axis of said spindle with said surfaces spaced from one another rearwardly of said line of contact with said operating member in a raised position a bushing threadably mounted on said spindle below said operating member for adjustable movement therealong and a compression spring surrounding said spindle interposed between said bushing and said operating member urging said supporting member into its normal position.

6. A tilt mechanism as claimed in claim 5 wherein said operating member and said bushing have concentric sleeve elements telescopically overlapping to conceal said spring.

7. A tilt mechanism as claimed in claim 6 wherein said operating member is of low friction plastic material. 

1. A tilt mechanism for a chair or the like comprising: an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle an operating member having a bore concentric with said spindle and movable therealong and means urging said operating element into contact with said supporting member said supporting member and said operating member having cooperating cam surfaces including a curved cam surface on one of said members and a flat cam surface on the other of said members providing in the normal position of said members a transverse horizontal line of contact generally coincIdent with the axis of said spindle.
 1. A tilt mechanism for a chair or the like comprising: an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle an operating member having a bore concentric with said spindle and movable therealong and means urging said operating element into contact with said supporting member said supporting member and said operating member having cooperating cam surfaces including a curved cam surface on one of said members and a flat cam surface on the other of said members providing in the normal position of said members a transverse horizontal line of contact generally coincIdent with the axis of said spindle.
 2. A tilt mechanism as claimed in claim 1 further including stop means interposed between said headpiece and said supporting member limiting the extent of tilting movement thereof.
 3. A tilt mechanism for a chair or the like comprising: an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle, the bottom of said supporting member having a downwardly curved cam surface an operating member having a bore concentric with said spindle and mounted thereon for sliding movement therealong, said operating member having a generally flat upper cam surface in contact with the curved cam surface of said supporting member, providing in the normal position of said members a transverse horizontal line of contact generally coincident with the axis of said spindle with said surfaces spaced from one another rearwardly of said line of contact with said operating member in a raised position and means urging said surfaces into contact with one another and into said normal position.
 4. A tilt mechanism as claimed in claim 3 wherein said means urging said surfaces into contact with one another and into said normal position comprises a bushing mounted on said spindle below said operating member for adjustable movement therealong and a compression spring surrounding said spindle interposed between said bushing and said operating member urging said supporting member into its normal position.
 5. A tilt mechanism for a chair or the like comprising: an upright spindle having a vertical axis a headpiece mounted on said spindle a supporting member surrounding said headpiece and pivotally mounted thereon for rearward rocking movement about a transverse horizontal axis longitudinally forwardly spaced from the vertical axis of said spindle, the bottom of said supporting member having a downwardly curved cam surface stop means interposed between said headpiece and said supporting member limiting the extent of tilting movement between a normal position and a rearwardly tilted position an operating member having a bore concentric with said spindle and mounted thereon for sliding movement therealong, said operating member having a generally flat upper cam surface in contact with the curved cam surface of said supporting member, providing in the normal position of said members a transverse horizontal line of contact generally coincident with the axis of said spindle with said surfaces spaced from one another rearwardly of said line of contact with said operating member in a raised position a bushing threadably mounted on said spindle below said operating member for adjustable movement therealong and a compression spring surrounding said spindle interposed between said bushing and said operating member urging said supporting member into its normal position.
 6. A tilt mechanism as claimed in claim 5 wherein said operating member and said bushing have concentric sleeve elements telescopically overlapping to conceal said spring. 